NCHOOSE2 - all combinations of two elements

Y = NCHOOSE2(X) returns all combinations of two elements of the array X. It is the fast, vectorized version of NCHOOSEK(X,2). X can be any type of array. When X is a scalar integer > 1, it returns X*(X-1)/2.

Example:
nchoose2([10 20 30 40])
% -> 10 20
% 10 30
% 10 40
% 20 30
% 20 40
% 30 40

nchoose2({'a','b','c','d','e'})
% -> 'a' 'b'
% 'a' 'c'
% ...
% 'c' 'e'
% 'd' 'e'

See also nchoosek, perms
combn, nchoose, allcomb (on the File Exchange)